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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Aeronautical & Space Sciences
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Journal DOI :
The Korean Society for Aeronautical & Space Sciences
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Volume & Issues
Volume 25, Issue 6 - Dec 1997
Volume 25, Issue 5 - Oct 1997
Volume 25, Issue 4 - Aug 1997
Volume 25, Issue 3 - Jun 1997
Volume 25, Issue 2 - Apr 1997
Volume 25, Issue 1 - Feb 1997
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Quasi-Steady Aerodynamic Analysis of Propeller-Wing Interaction
Jung, Woo-Youl ; Cho, Jin-Soo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 2, 1997, Pages 1~1
A 3- dimensional quasi - steady aerodynamic interaction between the propeller and wing is analyzed using vortex ring elements. The flow is assumed to be inviscid and the linear compressibility is assumed. The quasi - steady interaction is computed for one complete rotation of a propeller in 10 degree phase angle increments with respect to the wing reference axis. The computed results are compared with the quasi - steady results using a lifting line theory and with the full unsteady results using a frequency domain panel method.
Turbomachinery Flow Calculations Using Unstructured Meshes
Kwon, Oh-Joon ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 2, 1997, Pages 11~11
A three-dimensional inviscid flow solver is developed far turbomachinery components using unstructured meshes. The numerical scheme is based on the Roe's flux-difference splitting with an explicit Rungs-Kutta time integration. To accelerate the convergence to steady state, local time stepping and implicit residual smoothing are applied. Three-dimensional unstructured tetrahedral meshes are obtained using an advancing-front technique. To better resolve the flow at the periodic boundaries between blades, the grid periodicity is strictly enforced. The numerical method is applied for flows through a turbine annular cascade, advanced turbine rotor blade rows with the tip clearance gap, and a turbine volute. The results are compared with analytical and experimental data fer validation.
Numerical Study on an Impinging Jet
Rew, Ho-Seon ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 2, 1997, Pages 23~23
To assess various two equation turbulence models, the standard
model(SKE), the Chen-Kim model(CKM), the low Reynolds model(LRM) and the renormalized Group model(RNG) were applied to an impinging jet. The distance(In) between the jet exit and the wall is 2. The velocity profiles, the turbulence intensity profiles and the shear stress profiles at various locations were compared with experimental data. Also the Nusselt Number variation along the wall was included in this study. RNG model showed better agreement than the others. But the calculation results of these two equation models did not predict the turbulent intensity and the shear stress very well.
Use of ENO Scheme in the Calculation of Compressible Transonic Cascade Flow
Choe, Chang-Ho ; Yu, Jeong-Yeol ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 2, 1997, Pages 32~32
A numerical study using ENO scheme has been performed to assess its applicability for the compressible flows such as transonic bicircular arc cascade flow and supersonic wedge cascade flow. To validate ENO scheme, the first order Burgers equation has been tested. ENO schemes of different orders are used and comparisons are made with the conventional upwind and central difference schemes. A good shock capturing capability of ENO scheme has been displayed for bicircular arc cascade flow. By the combination of using ENO and central schemes, a better shock capturing capability fir the bicircular arc cascade flow has been demonstrated. However, ENO scheme also shows instability for the supersonic wedge cascade flow calculation, which offsets high order accuracy.
Flow Characteristics of the Transitional Boundary Layer on the NACA0012 Airfoil
Kang, Shin-Hyoung ; Lee, Hyeon-Koo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 2, 1997, Pages 42~42
The transitional boundary layer on the NACA0012 airfoil is investigated at low Reynolds numbers. The streamwise mean and fluctuating velocity profiles and wall shear stress distribution are measured. Turbulent characteristics of the flow are different from the flat plate transitional flow. Double-peak distributions of the streamwise RMS fluctuating velocity in the near wall region during transition are observed, and the third peak is detected at the outer region of boundary layer at the initial stages of transition. Maximum values of RMS fluctuating velocity occur at
. Velocity fluctuations during transition is not intermittent and the amplitude i9 much larger than that of downstream turbulent region. The frequency characteristics are similar to those of flat plate flow in high adverse pressure gradient, however more sensitive to the adverse pressure gradient.
Sound Radiation from Elliptic Vortex Ring (I): Axis Switching Motion of Single Elliptic Vortex Ring
Ryu, Ki-Wahn ; Lee, Duck-Joo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 2, 1997, Pages 51~51
Far field acoustic pressures from the unsteady motion of the three-dimensional vortex filament are calculated numerically. An accurate numerical scheme for vortex filament motion is also developed and validated. An elliptic vortex ring is a typical example of the three-dimensional vortex filament, and it is generated from the elliptic jet exit. An elliptic vortex ring emits a strong sound signal due to significant distortion and streatching of the vortex filament. At the far field, the accoustic pressure is linearly dependent on the third time derivatives of the vortex positions. Therefore, a numerical scheme of high resolution is employed to describe in detail the elliptic vortex ring motions which are highly nonlinear. Discretized vortex filaments are interpolated by using a parametric blending function to remove a possible numerical instability, and the accuracy and efficiency of the scheme are validated by comparisons with the analytic solution of circular vortex ring interaction. Acoustic signals from the evolution of a single elliptic vortex ring are obtained with various aspect ratios of the axes. The calculated periods in the acoustic signals depend to a significant degree on the initial aspect ratio of the ring. The far field acoustic signals depend significantly on increasing aspect ratio of the elliptic ring.
Numerical Study for the Prediction of the Spray Flow in Confined Jets
Jeon, Heung-Shin ; Lim, Jong-Han ; Yoon, Jun-Kyu ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 2, 1997, Pages 62~62
The study on the prediction of the spray flow in confined jets has been carried out numerically Numerical method is based on the one-way coupling because the loading is
and the evaporation of spray droplets can be ignored. However, this study is different from the other studies using the one way coupling because turbulence effects on spray droplet dispersion are estimated. The analysis of the flow field in confined jets is performed by the SIMPLE algorithm and DDM is used as a model fur spray. The number of sample droplets issued from twin-fluid atomizer is randomly selected from the droplet size distribution equation by Nukiyama-Tanasawa. Results show that the spray flow in confined jets is greatly affected by the droplet size and flow pattern. In turbulence effects on spray droplet dispersion, interaction time of small droplets and flow is eddy life time. Small droplets are greatly affected by turbulence, but large droplets are little affected by it. The trajectories of large droplets are mainly dependent upon initial jet condition, that is initial velocity and jet direction
Stabilization Characteristics of the Diffusion Flame Stabilized by the Flame Holder with Fuel Injection
An, Jin-Geun ; Song, Gyu-Geun ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 2, 1997, Pages 73~73
In this study, the stabilization characteristics of diffusion flame formed in the wake of a flame holder with fuel injection were investigated. The fuel injection angles, turbulence generators, and auxiliary fuel injection are selected as parameters. With these parameters, the flame stability limits, distribution of turbulence intensity, and concentration distribution of combustion gas were measured. The flame stabilization characteristics can be improved by change of fuel injection angle. The turbulence intensity in the wake of flame holder is increased and the flame stabilization characteristics is deteriorated with increase of diameter or blockage ratio of grid. If the stabilization characteristics of flame is good, the concentration of
is high, but the concentration of
is low at the boundary of recirculation zone. Finally, It is clear that the stabilization characteristics of diffusion flame can be improved by change of fuel injection angle, or injection of auxiliary fuel into the recirculation zone.
A Numerical Simulation of Axisymmetric Solid Rocket Motor Ignition Transient with Radiation Effect
Cho, In-Hyun ; Baek, Seung-Wook ; Chang, Suk-Tae ; Cha, Hong-Suk ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 2, 1997, Pages 81~81
A numerical simulation is performed to analyze the ignition transient in a solid rocket motor by employing time-dependent compressible SIMPLER algorithm fur gas phase governing equations and FVM for radiative transfer equation. Two dimensional conduction equation fur propellant grain is also coupled. The standard
model with wall function is used far turbulence. A reasonably good agreement with the experiment is obtained in predicting a variation of head end pressure. Based on this comparison, a detailed development of unsteady flow and temperature fields obtained is helpful for understanding the physic phenomena involved. Especially, the radiation is found to play a significant role in igniting the solid propellant by promoting the heat feedback to propellant surface.
Numerical Analysis of Combustion Performance in a Lean-Premixed Low-NOx Combustor
Hwang, Yeong-Hak ; Lee, Yeol ; Kim, Jin-Gon ; An, Guk-Yeong ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 2, 1997, Pages 89~89
Recently the lean-premixed combustors are drawing a considerable attention for reduction of harmful emissions from gas-turbine engines, such as NOx The amount of the NOx emitted from the engine is dependent on the various configuration of the combustor inside the engine. For different configurations of fuel injection orifices and two different fuel types, a numerical analysis was performed on the combustion characteristics of a premixed combustor with tangential entry (TE) nozzle, which was developed by the United Technology Research Center (UTRC). The present numerical calculation revealed that the combustion phenomena were generally concentrated near inner wall of the combustion-chamber, and observed that high-temperature-flames penetrated into the TE nozzle. Also the results of the calculation for a gaseous fuel, methane, showed a good comparison with the experimental results obtained by UTRC fur a similar condition. Finally, in the present study, the optimized configuration of orifices for a liquid fuel, pentane, to reduce NO was proposed.
A Study on Prediction of Ignition Onset Time for a Solid Rocket Motor
Jung, Jin-Suk ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 2, 1997, Pages 98~98
Prediction of ignition onset time far a solid rocket motor is very important for design analysis of rocket motor and igniter. In order to predict ignition onset time, it is necessary to know delivered heat flux to the motor propellant and required heat flux to ignite motor propellant. The former, it will be obtained from explaining heat transfer phenomena when igniter gas is exhausted in the motor chamber. The latter, it will be obtained from arc-image ignition data which is relatively simple and useful experimental one in labaratory. In this study, for several igniter models in the same rocket motor, ignition onset times were predicted theroretically. Comparing this prediction with the results of motor firing tests, the validity of this prediction method is presented.
An Experimental Study on Characteristics of Chemiluminescence Emission of Doubled Jet Burner Flame
Choe, Gyeong-Min ; Jang, In-Gap ; Choe, Byeong-Ryun ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 2, 1997, Pages 106~106
In industrial combustor, high loading combustion is pursued to accomplish a small-sized eqipment. Turbulent premixed flame is advantageous to high loading combustion. And in this case, turbulent burning velocity is an important factor that determines combustion loading. Since the turbulent burning velocity of distributed reaction flame is higher than that of wrinkled laminar name, distributed reaction flame is watched industrially. We measured overall averaged radical luminescence intensity with image processing system and then made a comparing study of combustion characteristics. And we measured local radical luminescence intensity with local measuring system, and researched chemiluminescence emission characteristics. As a result, the radical luminescence intensity distribution through the image processing system is useful to elucidate the characteristics of general burner flame. The distribution of CH radical luminescence intensity shows similar trend with that of local equivalence ratio. When the turbulent intensity is increased with central direction flux, doubled jet burner flame coresponds to the distributed reation flame judging from the distribution of fluctuating temperature, radical luminescence intensity and local equivalence ratio. And in the strong turbulence field of doubled jet burner, the radical luminescence randomly exists due to small size eddies.
A Study on the characteristics of the liquid sheet formed by Swirl Injector
Park, Byeong-Seong ; Kim, Seon-Jin ; Gang, Gyeong-Taek ; Kim, Yu ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 2, 1997, Pages 117~117
An experimental study on the characteristics of the liquid sheet formed by swirl injector was carried out to determine the effects of geometric design parameters and pressure drops on the discharge coefficient and dispersion an91e and breakup length. The geometric parameters included: 1) the shape of swirler inlet, 2) post length to diameter ratio. The design of injectors are based on the
thrust hybrid rocket using the liquid oxygen as a oxidizer and the HTPB as a fuel. The cold test using water as a simulant liquid was conducted. The major conclusions that resulted from this study are as fellow: 1) discharge coefficients decreased with increasing the number of swiller inlet, but the pressure drops have no effect on the discharge coefficients. 2) with increasing the number of swirler inlet, dispersion angle increased but breakup length decreased. 3) with increasing the post L/D, dispersion angle decreased but breakup length increased. 4) with increasing pressure drop, dispersion angle increased but breakup length decreased. 5) increasing dispersion angle result in decreasing breakup length.
Supersonic Flutter Analysis for Composite Panels under Thermal Loading
Moon, Seong-Hwan ; Jung, Sung-Nam ; Kim, Seung-Jo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 2, 1997, Pages 124~124
In this study, the flutter analysis for composite panels in a supersonic flow is performed using the finite element method. The quasisteady first order piston theory is adopted as an aerodynamic model and the von Karman's plate theory capable of considering the geometric nonlinearity is used as structural model to capture the large deflection behavior of panels. The effects of temperature change which are significant factors in supersonic flow are considered in the present formulation. The constitutive equations for laminated composite plates are introduced. The equations of motion for a panel under combined thermal and aerodynamic loads are derived from the principle of virtual work. The flutter boundary of panels is predicted by an eigenvalue analysis. The static post-buckling and the dynamic analysis are carried out using the Newton-Raphson iterative technique and the Newmark nonlinear time integration method. Through a time integration scheme, the panel state and the dynamic responses of panel with dynamic pressure increase are presented. The characteristics of limit-cycle oscillation, periodic motion, and chaotic motion in a phase plane are also shown. Finally, the flutter characteristics of the panel with respect to ply angle changes are identified.
Gradual Aeroassisted Orbital Plane Change via Sliding Mode Control
Lee, Sang-Uk ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 2, 1997, Pages 133~133
Orbital plane change maneuvers of hypervelocity vehicles during synergetic flight using aerodynamic farces is considered. The sliding mode control scheme is introduced to obtain control laws for the maneuvers. A model which consists of linear equations for perturbed motion with respect to a great circle trajectory about a non-rotating earth was used in terms of variables which low uncoupling of the longitudinal and later dynamics, and partial uncoupling of lateral dynamics.
Comparison between Quaternion Error Model and Equivalent Tilt Error Model
Lee, Hyung-Keun ; Lee, Jang-Gyu ; Rho, Young-Kyu ; Park, Chan-Gook ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 2, 1997, Pages 142~142
In this paper, we compare the linear quaternion error model(LQEM) and the linear equivalent tilt error model(LETEM) both of which are widely used fur the analysis of the strapdown inertial navigation systems(SDINS) based on the quaternions. Since the major difference between them occurs due to the approximations of the attitude error, this paper focuses on the modeling accuracy with respect to the attitude error. For the comparison, we derived a nonlinear error model which includes all the higher order terms of the attitude error. Using the derived nonlinear error model, the difference between LQEM and LETEM was analytically revealed. As a substitute for LQEM and LETEM, a linear error model which improves modeling accuracy with respect to the attitude error was also derived. Finally, a simple simulation far verification was performed.
Development of a generic structural optimisation sizing technique for commercial transport aircraft wing box
Park, Mun-Sik ; Bae, Dong-U ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 2, 1997, Pages 155~155
A structural sizing methodology and its procedures are described in this paper fer the swept wing box design of a commercial transport aircraft. A multidisciplinary optimisation tool is implemented based upon the developed methods using Microsoft Excel 5.0 and Visual Basic. It incoporates and integrates data such as planform parameters, nondimensiional aerodynamic lofts, structural arrangements, loads and databases dealing with material properties and design criteria. It ensures designers not only to browse the results in tabular or graphic form but also to cater for the design by their knowledge or experience. An interpolation method to determine structural airfoils from those of the streamwise direction is described. Nonlinear curve fitting techniques to formulated complex design allowable charts, accurate calculation of stiffness and stress, and a robust design update and iteration procedures are key ideas in this study. A sizing tool giving data fur the detail design is realized based on strength and stiffness. A more detailed sizing method which includes stress and fatigue analysis, dynamic loads, pad-ups and other design considerations, would be the next.
Aircraft Noise Evaluation and Model Testing Techniques
Choi, Jong-Soo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 2, 1997, Pages 167~167
Aircraft Noise Sources and its Prediction Method
Jeon, Wan-Ho ; Lee, Duck-Joo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 2, 1997, Pages 175~175
Propeller Noise : Principles, Analysis and Reduction Methods
Lee, Soo-Gab ; Choi, Seong-Im ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 25, issue 2, 1997, Pages 183~183